钠铝辉石由非晶态到晶态的转化研究

在3.0－5.0 GPa，1150－1750 ℃，1－480 min条件范围内，合成了钠铝辉石，通过XRD、SEM及IR分析对比研究了人工翡翠和天然翡翠的微观精细结构；通过DAT分析测定了人工翡翠与天然翡翠的熔点，淬火实验检验了人工翡翠的熔点，通过退火及老化实验研究了翡翠的热稳定性。同时还就人工翡翠和天然翡翠的硬度、密度及折射率等其它物化性质进行了比较研究。根据上述研究总结了合成优质钠铝辉石翡翠的最佳实验条件为压力＞4.0 GPa，温度＞1450 ℃，晶化时间＞45 min。

Crystallization of Clinopyroxene NaAlSi_2O_6 from Glass

Clinopyroxene NaAlSi_2O_6 was synthesized under varying pressures of 3.0-5.0 GPa and at the temperature range of 1150-1750 ℃, for periods of 1-480 min. The glass material was completely transformed into homogeneous penetrating fibrous texture of clinopyroxene NaAlSi_2O_6 when the crystallization was carried out on the optimum condition beyond 4.0 GPa, 1450 ℃, and 45 min . The microstructure of synthetic clinopyroxene NaAlSi_2O_6 was very similiar with that of natural one. Penetrating fibrous grains of the clinopyroxene were highly ordered when the sample was synthesized at above optimun crystalline condition.
The six-fold coordination of the Al~(3+) in the presence of Si~(4+) in clinopyroxene NaAlSi_2O_6 was transformed into four-fold coordination of the Al~(3+) in both nepheline NaAlSiO_4 and albite NaAlSi_3O_8 after it was treated at 1.013×10~5 Pa and 1173 K for 24 hrs. The other preconceived physical and chemical properties of synthetic clinopyroxene was highly consistent with those of the natural sample. The clinopyroxene doped with Cr~(3+), NaAlSi_2O_6: Cr~(3+) (0.5-1.0wt%), which was synthesized beyond the optimum crystalline condition, was of brightness and, hardnes, compact, emerald, translucence.